Drop this to an i5-2500K for gaming - you only need the i7 if you're using some super high-end rendering and video and photo editing applications.
PSU: COUGAR-GX1050 1050W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS GOLD Certified Modular Active PFC Power Supply
I've heard mixed things about this PSU maker - and you certainly don't need to use a 1050W PSU for this build. You could drop this to 950 or 850 to be on the safe side and still have plenty of wattage left over. Invest the difference in a good cooling solution like the Noctua NH-U9B or you could even get a Corsair H100 for the price.
Memory: G.SKILL Sniper Low Voltage Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBSR2
Not sure I'd go low voltage in an SB build - you get the wrong voltage of RAM and that could potentially fry your build. No matter what board you go with you should *ALWAYS* check the compatible memory guidelines from the manufacturer's support site and that will give a good idea of what works and what doesn't. You can always e-mail the manufacturer too and see what they recommend and if they've tested that part with the board in question.
GPU: XFXFX HD-697A-CNFC Radeon HD 6970 2GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity
XFX is a pretty decent GPU maker but if you're going Radeon you should get the 2GB 6950 model - you can flash the BIOS and it will perform equivalent to the 6970 and it will save you between $60 - $70. Personally I like Sapphire the best for Radeon - I've bought a few cards over the years and they've all been quite excellent.
Hard Drive: still looking
How much are you looking to spend here? If you take into account what I've recommended you can slash about $300 off the cost of this build. And with that you should invest the difference in getting a good 64GB SSD like the Crucial M4 or Samsung 830, and a Samsung 1TB Spinpoint as the secondary, that will give you plenty of storage and it will be blazing fast.
I'd stick with the motherboard and case you have now - they're both pretty good choices.